In U.S. Pat. No. 4,303,601, entitled "Ventilator-Humidifier," there is disclosed a system for providing humidified air or other gas to a patient. Air or other gas is directed to the humidifier where the gas is saturated by the humidifier. The saturated gas is fed through tubing which extends to the patient. The airway temperature of the humidified gas (at the airway opening adjacent the patient's mouth) is different from the temperature of the gas adjacent to the humidifier. A temperature probe is provided adjacent the airway opening for feedback control of the temperature.
It is important that the temperature probe be located correctly adjacent the airway opening. Because the temperature probe is located in the tubing at a point that is remote from the heater, it is desirable to detect if the temperature probe is correctly located prior to the time that the delivered gas reaches an undesirable high temperature.
Although the illustrative embodiment concerns the detection of the presence of a temperature probe in the air delivery tubing connected to a feedback-controlled heated humidifier that is used for delivering humidified gases to a patient, it is to be understood that the present invention is applicable to the detection of any temperature sensor located in a heating conduit at a point that is remote from the heater.
Therefore, it is an object of the present invention to provide a process for detecting if the temperature sensor is correctly located in a heating conduit at a point that is remote from the heater, before the heated fluid, e.g., gas, reaches an undesirable high temperature.
Another object of the present invention is to provide a system which is operational to detect if the temperature sensor has been removed from a heating conduit during operation of the system.
Other objects and advantages will become apparent as the description proceeds.